4.0 RC 2: Object::cast_to<() returns nullpr

[sash-rc]

4.0 RC 2 (Linux x86_64 gcc)

auto node1 = get_node_or_null("gui"); // valid
auto node2 = Object::cast_to<Control>(node1); // nullpr
auto node3 = get_node<Control>("gui"); // nullpr

[Withaust]

Also broken by #1037

[dsnopek]

Can you share a minimal reproduction project?

I attempted to reproduce the issue, but was unable to - here's my project: object-cast-to-test.zip

The core of my project is a GuiNode class that looks like this:

void GuiNode::_ready() {
    Control *gui = memnew(Control);
    gui->set_name("gui");
    add_child(gui);
}

void GuiNode::_bind_methods() {
    ClassDB::bind_method(D_METHOD("do_something"), &GuiNode::do_something);
}

void GuiNode::do_something() {
    auto node1 = get_node_or_null("gui");
    auto node2 = Object::cast_to<Control>(node1);
    auto node3 = get_node<Control>("gui");

    printf("node1 = %p\n", node1);
    printf("node2 = %p\n", node2);
    printf("node3 = %p\n", node3);
}

In the game (in the game/ directory), there's a simple GDScript that does:

func _ready() -> void:
	var n = GuiNode.new()
	add_child(n)
	n.do_something()

In my testing, it's printing out a valid pointer for all three cases!

I suspect there's another bug somewhere that affects certain ways of creating Godot objects, which was simply exposed by the change in PR #1037. So, we'll really need to see how your nodes are created in order to track down where the problem is.

[sash-rc]

@dsnopek
Sorry, I don't use SCons for my projects. But to reproduce a case, in a stock demo project, in test/src/example.cpp
append this code to void Example::_notification(int p_what) (after line 52)

if  (p_what == NOTIFICATION_READY) {
  auto just_node = get_node_or_null("Label");
  auto label_node = get_node<Label>("Label");
  auto cast_node = cast_to<Label>(just_node);
  UtilityFunctions::print("NOTIFICATION_READY, just_node: ", just_node, " label_node: ", label_node, " cast_node: ", cast_node);
}

It prints

NOTIFICATION_READY, just_node: Label:<Label#26608664999> label_node: <Object#null> cast_node: <Object#null>

Built with "editor" target, if this matters.

[dsnopek]

@sash-rc In your example, how is the "Label" node created?

[sash-rc]

@dsnopek

how is the "Label" node created?

It's a part of demo scene, a child of Example node. Stored in test/demo/main.tscn

[dsnopek]

It's a part of demo scene, a child of Example node. Stored in test/demo/main.tscn

Oh, ok, you're using the demo project in this repo! Sorry, I didn't pick up on that from your original comment. Thanks!

[codecat]

This caused some issues in TBLoader as well: codecat/godot-tbloader#68 and codecat/godot-tbloader#69

[RonYanDaik]

on windows fails to cast.

Object* oub = Object::cast_to<Object>((Object*)selected_array[x]); //success
Node* noub = Node::cast_to<Node>((Object*)selected_array[x]);	  //failure
Node* noub2 = Node::cast_to<Node>(selected_array[x]);		//failure

//- then ---------------------------------------------------------------------------------
Node3D* nub = (Node3D*)(oub);					//success
Node3D* nub2 = Node3D::cast_to<Node3D>(oub);			//failure

//-- and to test if cast_to is working at all --------------------------------------------
Node* tub = nub->find_child("UnitBase");				//success
Node3D* ub = Object::cast_to<Node3D>(tub);				//success

[dsnopek]

FYI, the change that is causing these issues is going to be reverted (Remi approved it but hasn't gotten around to merging it yet):

#1046

I do have a set of PR's that fix these regressions without reverting (since reverting will add some other bugs back :-)), but the changes are too big with 4.0's imminent release.

In any case, thanks for the extra info on how to reproduce, but this issue should be fixed very soon once the revert PR is merged. :-)